(a) Field of the Invention
The present invention relates to a control method and apparatus of a vehicle including a drive motor, and more particularly, to a control method and apparatus of a vehicle including a drive motor in which braking control and shift control are improved by increasing the torque of the drive motor to a predetermined value when the shifting condition is satisfied during the driving by the braking or the inertia.
(b) Description of the Related Art
An environmentally-friendly technology of a vehicle is a core technology which controls survival of a future automobile industry, and advanced vehicle manufacturers have focused energy on the development of environmentally-friendly vehicles to satisfy environmental and fuel efficiency regulations. Therefore, vehicle manufacturers have developed an electric vehicle (EV), a hybrid electric vehicle (HEV), a fuel cell electric vehicle (FCEV), and the like, as future vehicle technologies.
The vehicle manufacturers have researched the hybrid electric vehicle as an alternative to solve problems such as satisfaction of exhaust gas regulations and enhancement of fuel efficiency performance, and have steadily performed research and development to commercialize the hybrid electric vehicle. In general, the electric vehicle, the hybrid vehicle, and the fuel cell vehicle are driven by a drive motor obtaining torque through electrical energy.
Particularly, the hybrid vehicle is a vehicle that uses two or more power sources, and an engine and a drive motor are used as the power sources of the hybrid vehicle. The hybrid vehicle uses an optimal operational range of the engine and the driving motor, and recovers energy during braking to to improve fuel efficiency and use energy efficiently. The vehicle having the drive motor operates the drive motor as a generator while driving by braking or inertia to recover braking or inertia energy, thereby charging the battery. In particular, the torque of the drive motor has a negative value and provides a braking force operated in a direction opposite to the driving direction of the vehicle.
Further, the vehicle having the drive motor may be required to down-shift while driving with the braking or inertia. While performing the down-shift, a speed (i.e., a speed of the drive motor) of the input shaft of the transmission is increased to a speed corresponding to a target shift state. In particular, according to the conventional shift control method, to improve the shift quality, an absolute value of the torque of the drive motor is adjusted using a torque intervention method, and engagement and disengagement of an off-going element and an on-coming element of the transmission is performed.
However, according to the conventional shift control method, while performing the down-shift, when the required braking amount of the driver is changed based on the operation of the brake pedal, a regenerative braking requirement amount is changed, and as a result, the torque of the drive motor (i.e., the torque of the input shaft of the transmission) is changed, and thus, it may be difficult to estimate the torque of the output shaft of the transmission. Accordingly, since it may be difficult to estimate a regenerative braking performance amount that corresponds to the torque of the output shaft of the transmission, it may be difficult to divide the braking amount that must be actually provided to the vehicle into the regenerative braking performance amount and a friction braking amount of the brake.
The above information disclosed in this section is merely for enhancement of understanding of the background of the invention and therefore it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art.